Morgan testified via video on Tuesday before a U.K. panel investigating media ethics about listening in on a telephone message from former Beatle Paul McCartney to his now ex-wife Heather Mills.

In a 2006 article he wrote for the Daily Mail tabloid, Morgan said he was played the message left by McCartney on Mills' answering machine where McCartney serenades Mills in an attempt to salvage their marriage.

Mills has stated that there was no way the former tabloid editor could have obtained the message honestly.

Morgan refused to divulge any details on how he obtained the message.

"I'm not going to discuss where I heard it or who played it to me," Morgan said in the testimony, according to AP.

When inquiry Chief Lord Justice Brian Leveson questioned Morgan on whether or not he had any evidence to prove he had obtained the message legally, Morgan said he could not provide any.

"I can't start any trail that leads to the identification of a source," said Morgan, according to AP.

Senior executives from Rupert Murdoch's News Corp. media juggernaut have already been fired, over a dozen journalists have been arrested, and U.K. police officers have resigned over their failure to investigate the hacking scandal.

Because Morgan’s testimony was under oath, he could face criminal proceedings if the panel finds he has violated any British laws.

The investigation focuses on when Morgan ran two British tabloids - The Daily Mirror, which he was with for nearly a decade, and Murdoch's News of the World, a publication which has since been shutdown amidst the scandal.

Morgan said he "doesn't believe" he ever listened to hacked voicemail messages and denied having contact with private detectives suspected of assisting the tabloid in unethical deeds, AP reported. Morgan also brushed off a mention of an earlier interview on phone hacking where he was quoted as saying "loads of newspaper journalists were doing it."

"My memory's not great about this. It was a long-time ago," Morgan said, when asked about his sources, according to AP.

Morgan admitted he used the services of Benji "the Binman" Pelham, a freelancer who specializes in searching through celebrities' trash for information.

"Did I think he was doing anything illegal? No. Did I think he was doing anything on the cusp of unethical? Yes," Morgan said in his testimony, according to AP.

In July, Rupert Murdoch also denied any involvement in the hacking scandal. News Corp. said in a statement on Tuesday that the company had already settled claims with people victimized by the scandal, including ex-Liberal Democrat lawmaker Mark Oaten, Princess Diana's former boyfriend James Hewitt, and model Abi Titmuss, and Paul Dadge, who helped rescue victims of the London train bombings in 2005.

Actress Sienna Miller received close to $157,000 in a settlement with News International, while the family of a slain British girl was granted $3.1 million, with an additional $1.6 million from Murdoch that he earmarked for charity.

British Police say the number of potential victims of the phone hacking scandal could be in the thousands.